Before the 60's, mortality decline affected mainly the babies and children. Therefore, when it happened, the proportion of the age groups under 15 was raised. As a result, the population underwent a younging process. The paradox was not understood by all observers. Since the 70's, demographic change took another direction. There was a significant mortality decline and it concerned mainly the ages over 60. The move increased the number and proportion of the elderly (population aging). Moreover, from 2006 onwards, the baby boom cohorts born during the period 1946-1966 will arrive successively to the retirement age. The process will be an other strong factor of population aging. However, the elderly of the year 2020 will be likely different from the elderly of the 90's. More educated, better cared by a more efficient health system, but more affected during their adulthood by unemployment and family unstability, living themselves in an older universe, they will have new behaviors, and will express perhaps unknown demand.